Molecular Biology Commons^™

Parameterizing Ion–Lipid Interactions From Local Clusters To Reproduce Experimental Bulk Properties Of Lipid Bilayers, W. Matthew Saunders

USF Tampa Graduate Theses and Dissertations

Phospholipids are the main component of cell membranes, providing a delimiting boundary for cells from their environments or from their organelles from the cytosol. Thiscompartmentalization allows cells to maintain quite different solutions within their cells and organelles, including different mixtures dissolved ions. Consequently, these membranes are constantly flanked by complex mixtures of salts at varied concentrations. To study membrane structure, one cannot neglect the contribution of the salts in the local solution. Ions perturb bilayer structure via specific interaction with the phospholipids, primarily with the headgroups. Experimental studies of these systems are somewhat at odds — scattering experiments with different …

Improving Coral Restoration Outcomes Through Novel Molecular Applications, Matthew H. Gamache

USF Tampa Graduate Theses and Dissertations

Coral reef ecosystems are declining globally from numerous stressors, including localized pollution, disease, and marine heatwaves induced by climate change. To preserve these ecosystems, it is critical to identify corals that can withstand stressors—primarily future marine heatwaves—and prioritize them for coral restoration efforts until these stressors are mitigated. Coral responses to thermal stress can be influenced by several partners, including mutualistic microalgae and a vast prokaryotic community. Here, I use advanced molecular techniques to examine which partners (coral host, algal symbiont, and microbial communities) are associated with coral health, how they contribute to holobiont physiology, and their potential to increase …

Dnajb6: A Potent Dnajb Chaperone In Regulating Tau Proteostasis, Abigail R. Esquivel

USF Tampa Graduate Theses and Dissertations

Neurodegenerative diseases often feature the pathological buildup of misfolded proteins, and tau is a principal culprit in multiple tauopathies. One chaperone of emerging interest is DnaJB6b, a member of the Hsp40/DnaJ family, which exhibits potent anti-aggregation activity against several disease-related proteins. Recent investigations highlight its unique capacity to recognize and neutralize aggregation-prone forms of tau. DnaJB6b appears potent against multiple variants of tau and may be acting against tau, in part, by directing misfolded tau toward proteasomal clearance. The first lines of evidence come from systematic chaperone screens, where DnaJB6b repeatedly emerged as a strong suppressor of tau seeding. Further …

A Phenotypic Characterization Of Staphylococcus Aureus Bacteremia Clinical Isolates, Sara Dj Daniels

USF Tampa Graduate Theses and Dissertations

Staphylococcus aureus is a human pathogen of serious concern because of its ability to cause serious and wide-ranging disease. Of particular concern is the ability of S. aureus to cause bacteremia (SAB), allowing the bacteria to disseminate and spread to various organs. This study addressed this issue through the phenotypic characterization of two methicillin-resistant S. aureus (MRSA) clinical isolates taken from patients with sustained complicated bacteremia at Tampa General Hospital, referred to as SA1097 and SA1098. A battery of phenotypic tests was conducted on these strains, including a growth curve, hemolysis and proteolysis screenings, cytotoxicity assays using human neutrophils, blood …

Selective Pericyte Recruitment To Ec-Lined Tubes, Vessel Assembly Enhancement Through Pericyte Timp-3 Induction, And Pericyte Tbx2 In Capillary Formation And Maturation, Ksenia Marilyn Yrigoin Kaluguina

USF Tampa Graduate Theses and Dissertations

Capillaries, the smallest blood vascular networks, are formed by narrow and elongated endothelial cell (EC)-lined tubes with associated pericytes anchored to the abluminal tube surface. Our laboratory demonstrated that dynamic interactions between ECs and pericytes during capillary tube network assembly are required for basement membrane matrix deposition and maturation. We have also shown that key EC-derived factors promote pericyte recruitment, proliferation, and pericyte-induced basement membrane formation during capillary assembly. In the first section, we aim to identify if vascular smooth muscle cells (VSMCs) respond to the same factors and have the same invasive ability as pericytes since they are both …

Rictor, A Mtorc2 Protein, Regulates Lymphatic Valve Formation And Maintenance Through The Akt-Foxo1 Signaling Axis, Richa Banerjee

USF Tampa Graduate Theses and Dissertations

The lymphatic vasculature maintains tissue fluid homeostasis by absorbing interstitial fluid to form lymph and transporting it back to the bloodstream. Collecting lymphatic vessels have lymphatic valves (LVs) that prevent the retrograde flow of lymph generated by hydrostatic pressure from the blood vasculature. Backflow and accumulation of lymph leads to a lymphatic pathology called lymphedema. This implicates the involvement of defective LVs in the pathogenesis of lymphedema and warrants the study of lymphatic valve development and maintenance. The LVs are formed through a process called mechanotransduction which signals through the intracellular PI3K-AKT pathway in lymphatic endothelial cells. However, the activation …

Malat1 Mediates Tet2 Loss Of Function-Driven Oncogenic Inflammation Via Rna Shielding Of Nf- Kappa B P65, Nana Adjoa Ben-Crentsil

USF Tampa Graduate Theses and Dissertations

TET2 is a dioxygenase that regulates gene expression and hematopoiesis by oxidizing 5-methylcytosine residues on DNA to 5-hydroxymethylcytosine. TET2 mutations are common genetic events in hematological disorders. For example, TET2 is the most frequently mutated gene in Chronic Myelomonocytic Leukemia and occurs in about 33% of other myeloid malignancies. It is also the second commonest mutation in clonal hematopoiesis of indeterminate potential (CHIP), a common premalignant condition in the elderly. TET2 mutations arise in founding clones and are implicated in many non-hematological sequelae seen in CHIP like atherosclerotic disease, chronic liver disease, and severe microbial infections.

The development of TET2-deficient …

Roles Of Mitochondrial Chchd2 And Gpcr-Associated Β-Arrestin2 In The Pathogenesis Of Lewy Body Disorders, Teresa R. Kee

USF Tampa Graduate Theses and Dissertations

Coiled-coil-helix-coiled-coil-helix domain containing 2 (CHCHD2) is a mitochondrial protein that plays important roles in cristae structure, oxidative phosphorylation, and apoptosis. Multiple mutations in CHCHD2 have been associated with Lewy body disorders (LBDs), such as Parkinson’s disease (PD) and dementia with Lewy bodies (DLB), with the CHCHD2T61I mutation being the most widely studied. We generated the first transgenic mouse models expressing human CHCHD2WT and the PD-linked CHCHD2T61I mutation driven by the mPrP promoter. CHCHD2T61I Tg, but not CHCHD2WT Tg mice exhibit perinuclear mitochondrial aggregates, neuroinflammation, and have impaired long-term synaptic plasticity associated with synaptic dysfunction. Dopaminergic neurodegeneration, a hallmark of PD, …

Functional Studies Of Dcaf14 In Replication Fork Stability And Genome Integrity, Neysha Tirado-Class

USF Tampa Graduate Theses and Dissertations

The response to replication stress is critical for ensuring the stability of replication forks and preserving genome integrity. To aid this response, several factors are recruited to stalled replication forks to prevent irreversible collapse of the replication machinery. Replication fork proteomic analyses of stalled forks reveal enrichment of DCAF14, a component of the Cullin4-RING (CRL4) E3 ubiquitin ligase complex, that mediates replication fork protection by blocking nuclease-mediated digestion of nascent DNA. However, little is known about the molecular mechanism by which DCAF14 functions in the context of replication stress. Notably, loss of function mutations in DCAF14 are associated with a …

Group B Streptococcus Intestinal Barrier Disruption And The Protective Role Of Butyrate, Kristen Dominguez

USF Tampa Graduate Theses and Dissertations

Group B Streptococcus (Streptococcus agalactiae; GBS) is a leading cause of neonatal sepsis worldwide. Intrapartum antibiotics in GBS-colonized mothers significantly reduced the incidence of early-onset sepsis occurring in the first week of life; however, there are currently no prophylactic interventions for late-onset sepsis, occurring within the first 3 months of life. GBS is a pathobiont that primarily colonizes the gastrointestinal tract and can cross the intestinal barrier via both the paracellular and transcellular routes, causing invasive disease. Neonatal susceptibility to GBS intestinal translocation is mediated by inadequate epithelial barrier function and microbiome immaturity; however, the mechanisms by which GBS exploits …

Cornus Officinalis Extract Activates The Keap1/Nrf2 Pathway And Delays T1d Onset In The Nod Mouse, Justin D. Fletcher

USF Tampa Graduate Theses and Dissertations

Type 1 diabetes (T1D) is an autoimmune disorder that results in the destruction of the insulin producing pancreatic β cells. The only therapeutic option following T1D clinical onset is exogenous insulin supplementation. At present, there is no cure for T1D and attempted interventional therapy has been focused on modulating the immune system. Few attempts have been pursued at preserving β cell function and survival. Here we provide a novel approach using extract from the fruit of the Cornus officinalis (CO) tree to preserve β cell function through the prevention of β cell stress. CO has been used in traditional Chinese …

Macrophage-Driven Car T Cell Resistance In B Cell Lymphoma, Sae Bom Lee

USF Tampa Graduate Theses and Dissertations

Chimeric antigen receptor (CAR) T-cell therapy has revolutionized the treatment of patients with relapsed/ refractory large B cell lymphoma (LBCL). Despite its promising efficacy, a subset of patients experiences primary resistance or relapse. In Chapter 2, we explore the tumor microenvironment (TME)-induced resistance mechanisms in patients with LBCL. Analysis of the intratumoral immune infiltrates in pre-infusion tumor biopsies revealed that the levels of immunoregulatory macrophages were elevated in patients who responded poorly to axicabtagene ciloleucel (axi-cel). Using preclinical mouse B cell tumor models, we found that the CAR T-cell-produced interferon-gamma (IFN-γ) enhanced the expression of inducible nitric oxide synthase (iNOS, …

Tetr Family Regulator, Farr, Influences Rot-Mediated Control Of Virulence Factor Expression In Staphylococcus Aureus, Julia C. Schumacher

USF Tampa Graduate Theses and Dissertations

Point-mutation variants of the TetR family regulator, FarR, have emerged across Staphylococcus aureus sequence types as conferring antibiotic and fatty acid resistance, particularly in Hospital-Associated Methicillin Resistant S. aureus (HA-MRSA) strains. FarR also exhibits an additional largely uncharacterized relationship to virulence factor production, seemingly through the global repressor of toxins—Rot, which functions to regulate S. aureus’ ability to colonize and persist in the host via a complex cascade of signaling. While Rot protein is post-transcriptionally regulated by the highly characterized Agr system, there is little known about its transcriptional regulation. Herein, we explored these dynamics by initially characterizing virulence phenotypes …

Multivalency Of The Mdmx Acidic Domain Slims Use Different Binding Modes To Inhibit Mdmx And P53, Malissa Fenton

USF Tampa Graduate Theses and Dissertations

Regulation of protein binding through autoinhibition commonly occurs via interactions involving intrinsically disordered regions (IDRs). These intramolecular interactions can directly or allosterically inhibit intermolecular protein or DNA binding, regulate enzymatic activity, and control the assembly of large macromolecular complexes. Autoinhibitory interactions mediated by protein disorder are inherently transient, making their identification and characterization challenging. In this work, we explore the structural and functional diversity of disorder-mediated autoinhibition for a variety of biological mechanisms, with a focus on the role of multivalency and effective concentration. We also discuss the evolution of disordered motifs that participate in autoinhibition using examples where sequence …

Preliminary Investigation Of Differences In Host Mitochondria Membrane Potential During Toxoplasma Gondii Infection, Bryan L. Ortega

USF Tampa Graduate Theses and Dissertations

Toxoplasma gondii is an obligate intracellular protozoan with a broad host range of hosts, including various warm-blooded mammals, including humans. While infections can often be asymptomatic in immunocompetent individuals, they can pose significant risks to those who are immunocompromised, as well as pregnant women. Toxoplasmosis represents a significant burden on public health in the United States, with over 800,000 annual infections reported, often leading to severe complications such as symptomatic eye disease and congenital infections. Recent attention has developed regarding its potential association with human neuropathies such as Alzheimer's disease, dementia, and mood disorders. This project investigated differences in host …

Metatranscriptomic Insights Into The Interaction Between Microcystis Blooms And Hydrogen Peroxide, Taylor L. Hancock

USF Tampa Graduate Theses and Dissertations

For this dissertation I studied the interactions of hydrogen peroxide and cyanobacterial harmful algal blooms (cHABs) dominated by Microcystis in the Caloosahatchee River, FL. Specifically, I examined how taxonomic and functional succession relates to both natural hydrogen peroxide dynamics and hydrogen peroxide added to the environment as a cHAB treatment. Chapter 2 investigated how taxonomic succession and gene expression patterns relate to blooms and associated elevated hydrogen peroxide concentrations. The results showed that gene expressions related to cyanobacterial growth were positively correlated with hydrogen peroxide. The genes identified included enzymes capable of hydrogen peroxide generation which were expressed by blooming …

Androgen Drives Melanoma Invasiveness And Metastatic Spread By Inducing Tumorigenic Fucosylation, Qian Liu

USF Tampa Graduate Theses and Dissertations

Melanoma incidence and mortality rates are historically higher for men than women, with an estimated ~47% more new cases and twice the lethality in men in the US in 2023. Consistent with these discrepancies, emerging studies have highlighted the tumorigenic role of the male sex hormone androgen and its receptor (AR) in promoting melanoma aggressiveness. However, underlying cellular and molecular mechanisms and their precise pathological contributions are not well-defined. We recently discovered a sex-associated disparity in melanoma fucosylation, the post-translational modification of proteins with the dietary sugar L-fucose. Fucosylation, the conjugation of fucose moieties onto different glycan linkages on target …

Targeting Bet Proteins Downregulates Mir-33a To Promote Synergy With Pim Inhibitors In Cmml, Christopher T. Letson

USF Tampa Graduate Theses and Dissertations

Chronic Myelomonocytic Leukemia (CMML) is a rare myeloid malignancy with a dismal prognosis and no therapeutic options which are capable of altering the natural course of the disease. There remains a significant need for novel therapies that are able to meaningfully improve patient outcomes. In this study we explore the effectiveness of Bromodomain and Extra-Terminal domain protein inhibitor (BETi) combinations in CMML. Preclinical studies in myeloid neoplasms have demonstrated efficacy of BETi. However, BETi demonstrate poor single agent activity in clinical trials. Several studies suggest that combinations with other anti-cancer inhibitors may enhance the efficacy of BETi. To nominate BETi …

Neuroendocrine Regulation Of Chemokine Receptor-Mediated Leukocyte Migration Via Heteromeric G Protein-Coupled Receptor Complexes, Garrett Enten

USF Tampa Graduate Theses and Dissertations

Neuroendocrine regulation of the innate immune system is a well-documentedphenomenon. The underlying mechanisms, however, are not well understood. Here we show that at least 20 members of the human chemokine receptor (CR) family heteromerize with one or more members of the α1-adrenergic receptor (AR) family and that all CRs, apart from CXCR1, heteromerize with arginine vasopressin receptor 1A (AVPR1A) in recombinant systems. These heteromeric complexes are detectable in human monocytes and the monocytic leukemia cell line THP-1. Though currently technical limitations prevent the direct visualization of endogenously expressed higher-order hetero-oligomeric receptor complexes, we provide evidence through functional analysis and proximity-based …

Thermodynamic Frustration Of Tad2 And Prr Contribute To Autoinhibition Of P53, Emily Gregory

USF Tampa Graduate Theses and Dissertations

The intrinsically disordered transcription factor and tumor suppressor p53 binds to promoter response element DNA upon cellular stress and activates genes associated with cell cycle arrest, senescence, and apoptosis. Disruption of sequence specific binding to target gene promoters is heavily implicated in human health, where a majority of cancers contain mutations localized to the DNA binding domain (DBD) of p53. p53 DNA binding is regulated by posttranslational modifications, associations with cellular factors, and by an autoinhibitory intramolecular interaction. The autoinhibitory intramolecular interaction occurs when the disordered N-terminal transactivation domain (TAD) interacts with the ordered DBD. Previous work in the Daughdrill …

Role Of Short Interspersed Nuclear Elements (Sines) Of Maternally Imprinted Microrna Clusters In Hemochorial Placental Antiviral Immunity, Ishani Wickramage

USF Tampa Graduate Theses and Dissertations

The evolution of hemochorial placentas in which the fetal trophoblast is bathed in maternal blood has vastly improved fetal development and survival in primates and rodents, due to the enhanced efficiency of nutrient, gas and waste exchange between the mother and the fetus. However, the extensive contact between the fetal tissues and maternal blood in these placentas also poses an increased risk of vertical transmission of pathogens such as viruses from the mother to the fetus. In response to this selection pressure, hemochorial placentas have evolved robust defense mechanisms to protect the immunologically naive fetus. Unlike somatic cells that require …

Defining A Factor-Induced Signaling Signature For Endothelial Tubulogenesis, Sprouting, And Pericyte Recruitment, Prisca Kuanting Lin

USF Tampa Graduate Theses and Dissertations

Endothelial cells (ECs) form the inner lining of blood capillary walls. Our laboratory has developed a serum-free, defined Factor system that allows for human ECs to sprout, form lumens and tube networks, recruit pericytes, and induce capillary basement membrane deposition in 3D extracellular matrices. We have shown that the Factor system drives morphogenesis through the activation of multiple signaling pathways; however, we do not know if all factors in the Factor system are needed to induce maximal EC morphogenesis. If so, we have yet to identify why the Factors are critical to the model other than that they induce activation …

Novel Roles Of The Blm Syndrome Dna Helicase In Genome Maintenance And Mitochondrial Regulation, Brian B. Rodemoyer

USF Tampa Graduate Theses and Dissertations

Bloom syndrome (BS) is an extremely rare autosomal recessive genetic disorder caused by defects in the BLM gene. Patients with BS display a broad phenotypic spectrum including abnormally short stature, microcephaly, sun sensitivity, insulin resistance, perpetual oxidative stress, and a ~300-fold greater propensity for developing cancer than the general population. As such, BS patients typically do not live past their 20’s. The BLM gene encodes the BLM helicase, a member of the highly conserved RecQ family of 3’ to 5’ DNA helicases. Most of our cellular understanding of BLM is through its role in DNA damage repair through the homologous …

Withaferin A And Immune Checkpoint Blocker Therapy For The Treatment Of Non-Small Cell Lung Cancer, Roukiah Khalil

USF Tampa Graduate Theses and Dissertations

Lung cancer is the first cause of cancer-related deaths in both men and women with an overall five-year survival rate of 28%. Although immune checkpoint blockers (ICBs) are currently FDA-approved for the treatment of non-small cell lung cancer (NSCLC), only 17-20% of patients achieve durable responses by the induction of immunologic memory. The lack of response in most patients can be attributed to the tumor-intrinsic or tumor-extrinsic immune resistance mechanisms. A biomarker of importance is the Programmed Death Ligand-1 (PD-L1), as higher PD-L1 expression is usually associated with a better response to ICBs. Although studies have attempted to combine ICBs …

Exploring Strain Variation And Bacteriophage Predation In The Gut Microbiome Of Ciona Robusta, Celine Grace F. Atkinson

USF Tampa Graduate Theses and Dissertations

Current microbiome studies have shown that the maintenance of homeostasis betweenmicrobial populations (e.g. bacteria, viruses) and the host immune system (e.g. innate immune molecules) is necessary for balancing health and disease outcomes within the host. These studies most often utilize vertebrate models; however, research in this field can benefit from diverse model systems that facilitate our ability to conduct experiments to identify phylogenically conserved rules influencing homeostasis in the gut of animals. The Dishaw has developed the use of a filter-feeding marine invertebrate chordate, Ciona robusta, to model such fundamental interactions[1]–[6]. While most biological diversity and functional contribution within microbiomes …

A Novel Role For Enos In Regulating Lymphatic Valve Development During Embryogenesis, Drishya Iyer

USF Tampa Graduate Theses and Dissertations

Lymphedema is a disease that occurs when lymph flow is impaired, resulting in tissue swelling, fibrosis, chronic inflammation and recurrent secondary infections. Lymphatic valves play a critical role in maintaining unidirectional lymph flow and evidence for valve defects have been reported in lymphedema patients. The lack of drugs that can correct lymphatic valve defects warrants a better understanding of the molecular regulators of lymphatic valve development and maintenance. Lymphatic valves first develop during embryogenesis in response to mechanotransduction signaling pathways triggered by oscillatory lymph flow. Since eNOS (gene name: Nos3) is a well characterized mechanotransduction signaling molecule in blood vessels, …

A Forward Genetic Screen Identifies Genes Involved In Gametocyte Development Of The Human Malaria Parasite Plasmodium Falciparum., Jyotsna Chawla

USF Tampa Graduate Theses and Dissertations

Transmission of the deadly malaria parasite Plasmodium falciparum from human to mosquito is achieved by specialized intraerythrocytic sexual forms called gametocytes. Circulating in the vertebrate host, relatively few intraerythrocytic gametocytes are picked up during a bloodmeal to continue sexual development in the mosquito vector. Human-to-vector transmission thus represents an infection bottleneck in the parasite's life cycle for therapeutic interventions to prevent malaria. Though the crucial regulatory mechanisms leading to gametocyte commitment have recently come to light, networks of genes that control sexual development remain to be elucidated. Here, we report a forward genetic approach to identify genes associated with gametocyte …

Structural And Biochemical Characterization Of Epigenetic And Fusion Tyrosine Kinase Cancer Targets For Drug Development, Melissa Bikowitz

USF Tampa Graduate Theses and Dissertations

Cancer is a significant global health burden, as ~40% of the human population is diagnosed with cancer over a lifetime, half of which succumb to the disease. To develop novel compounds as potential cancer therapeutics, an in-depth structural and biochemical understanding of proteins involved in oncogenesis is key. This dissertation centers around the comprehensive structural and biochemical characterization of two classes of proteins critical for cancer cell survival: bromodomain-containing proteins (BRDs) and fusion tyrosine kinases (FTKs).In 2010, small molecule inhibitors targeting bromodomains (epigenetic reader proteins) became heavily popularized due to the druggability and potent anticancer effects of BET inhibitors. …

To Be Or Not To Be: A Tale Of Staphylococcal Gpsb, Lauren R. Hammond

USF Tampa Graduate Theses and Dissertations

There are two big drivers motivating studies into bacterial cell division. The first is a desire to understand life around us. One of the defining characteristics of life is the ability for a cell to grow and divide, and without in-depth knowledge of this process, we cannot truly understand the complexities that allow for life on this planet. The second motivator is to identify new drug targets in the ongoing fight against antimicrobial resistance. Many infectious organisms have become resistant to commonly used antibiotics, and the bacterial cell division machinery is a largely untapped essential process with many potential therapeutic …

Lord Of The Z-Rings: Uncovering The Role Of Mraz And Ftsl In Bacillus Subtilis Cell Division, Maria Louise White

USF Tampa Graduate Theses and Dissertations

Cell division is a complex and highly orchestrated process that requires careful coordination. The process of cell division in prokaryotes primarily occurs via binary fission, where one mother cell becomes two genetically identically and equally sized daughter cells. In most bacteria a key protein, FtsZ, forms a FtsZ ring (Z-ring) to mark the division site and recruit proteins involved in cytokinesis. Whilst much has been learned about the contents and assembly of the divisome in model organisms such as Escherichia coli and Bacillus subtilis factors governing the regulation of divisome are much more poorly understood. …